21S pre-rRNA is nucleolytically processed at site E (site2a) to yield 18SE pre-rRNA

Stable Identifier
Reaction [omitted]
Homo sapiens
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An unknown endonuclease in the nucleolus cleaves at site E (site 2a in mouse) of 21S pre-rRNA, yielding 18SE pre-rRNA (Preti et al. 2013, Sloan et al. 2013). Evidence also indicates that 18SE may also be produced by an exonucleolytic pathway (Carron et al. 2011, Sloan et al. 2013). BYSL (Bystin, ENG1), SKIV2L2 (MTR4), and the exonuclease activity of EXOSC10 (RRP6), all associated with the exosome, are required for formation of 18SE by the exonucleolytic pathway (Sloan et al. 2013). Sequencing indicates that 18SE molecules can have variable ends, presumably due to exonuclease activity (Preti et al. 2013).
Literature References
PubMed ID Title Journal Year
20805244 Analysis of two human pre-ribosomal factors, bystin and hTsr1, highlights differences in evolution of ribosome biogenesis between yeast and mammals

O'Donohue, MF, Carron, C, Faubladier, M, Choesmel, V, Gleizes, PE

Nucleic Acids Res. 2011
23439679 Both endonucleolytic and exonucleolytic cleavage mediate ITS1 removal during human ribosomal RNA processing

Lebaron, S, Sloan, KE, Mattijssen, S, Pruijn, GJ, Tollervey, D, Watkins, NJ

J. Cell Biol. 2013
23482395 Gradual processing of the ITS1 from the nucleolus to the cytoplasm during synthesis of the human 18S rRNA

Preti, M, O'Donohue, MF, Bortolin-Cavaillé, ML, Choesmel, V, Gleizes, PE, Montel-Lehry, N

Nucleic Acids Res. 2013
Catalyst Activity

3'-5'-exoribonuclease activity of EXOSC10:C1D:MPHOSPH6:SKIV2L2:Exosome [nucleoplasm]

This event is regulated
Orthologous Events
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